Various types of restraints have been used for restraining the loads which are carried in the trailers of large over-the-road trucks and semi-trailers. Shoring bars are often used in conjunction with tracks that are mounted on the opposite side walls of the truck or trailer body. Cargo bars that do not require tracks are also in widespread use. The cargo bar typically has pads on its opposite ends which bear against the truck walls (or the floor and ceiling) when a jack type ratchet mechanism is operated to lengthen the bar and wedge it in place. Often, a spring system known as a spring foot assembly is installed in the cargo bar to provide it with flexibility as the trailer walls flex. The need for a spring foot assembly increases the cost and complexity of the cargo bar construction.
One of the principal problems with cargo bars is that workers can operate the ratchet so aggressively that the cargo bar can apply excessive force to the trailer walls. At times, serious damage and even destruction of the truck walls can result. This can obviously lead to considerable cost and trouble. Hydraulic devices that have been used to apply the force have been provided with pressure relief systems that relieve the fluid pressure to avoid the application of excessive force. However, hydraulic systems are more complicated, costly, and difficult to use than mechanical cargo bars.
Another problem that has been encountered is that cargo bars can generally be used in only one orientation, with the ratchet handle projecting upwardly. At times, there is an advantage to orienting the cargo bar sideways with the handle projecting to the side for better access when applying and tightening the bar. In existing devices, the pawl of the ratchet mechanism drops to the side of the ratchet housing when the bar is positioned sideways. Then, the pawl cannot properly engage the teeth on the bar and cannot extend the bar as necessary for proper operation. For this reason, cargo bars are generally useful only in a position where the ratchet handle extends upwardly, and this is limiting as to accessibility of the handle.